Events Count Mode - Tektronix 7D11 DIGITAL DELAY Service Instructions Manual

Calibration-7Dll Service
EVENTS COUNT MODE
Equipment Required
1. I nd icator mainframe
2. Amplifier plug-in unit (dual-trace)
3. Time-base plug-in unit
4. Flexible plug-in extender
5. Square-wave generator
BEFORE YOU BEGIN, see
Set-Up
In the indicator mainframe, install a dual-trace amplifier
unit in either vertical compartment and a time-base unit in
either horizontal compartment. Within the 7011, discon-
nect P213 from the R F circu it board. Loosen the securing
screws and remove the RF board from the unit. Place the
7011 on the plug-in extender and plug the extender into
the remaining vertical compartment. Set the 7011 controls
as follows:
TRIGGER
SLOPE
LEVEL
COUPLING
SOURCE
EVENTS START TRIGGER
SLOPE
LEVEL
8 SWEEP DELAY MODE
COUNT MODE
FINE DELAY
+
Clockwise
AC
EXT
Clockwise
INDEPENDENT
EVENTS,
0.0
Y10. ChecK Events Start Trigger Sensitivity
a. Set the mainframe to display the amplifier and
time-base units.
b. Set the amplifier unit for dual-trace operation in the
chopped mode.
c. Connect a lOX probe to one of the amplifier-unit
inputs. Check the probe compensation. Set this channel for
a deflection factor of 50 millivolts/division (500 millivolts/
division at probe tip).
d. Connect the probe tip to TP 638 (on Logic board,
near the front of the unit).
e. Connect the medium-frequency signal generator to
the EVENTS START TRIG IN connector and to the other
input of the amplifier unit.
6. lOX probe
7. Low-capacitance screwdriver
8. IC probe tip
9. Three-inch screwdriver
10. Medium-frequency signal generator
11. Low-frequency signal generator
in the Diagrams section.
f. Set the signal generator for a 100-millivolt output at
two megahertz.
g. Set the time-base unit for auto, internal triggering at a
500 nanosecond/division sweep rate.
Vh. CHECK-Check that a display of the trigger-circuit
output can be obtained with the EVENTS START TRIG-
GER LEVEL control set at or near zero (midrange) in both
positions of the EVENTS START TRIGGER SLOPE
switch. Check also with the signal generator set for a 250
millivolt output at 20 megahertz and a 500 millivolt out-
put at 50 megahertz for instruments above SN 8050000
(300 millivolt at 4 megahertz and a 600 millivolt output at
50 megahertz for instruments below SN 8050000).
NOTE
When the conditions given in step 10h are met, the
dot on the EVENTS START TRIGGER LEVEL
knob should be aligned with the 0 on the front panel.
Component replacement or knob removal might
necessitate re-alignment. If so, loosen the setscrew
and reposition the knob.
i. Disconnect the medium-frequency signal generator
and connect the low-frequency signal generator to the
EVENTS START TRIG IN connector and to the amplifier
unit.
j. Set the low-frequency signal generator for a 100-
millivolt output at 30 hertz. Set the time-base unit for a 10
millisecond/division sweep rate.
Vk. CHECK-Check that a display of the trigger-circuit
output can be obtained with the EVENTS START TRIG-
GER LEVEL control set at or near zero (midrange) in both
positions of the EVENTS START TRIGGER SLOPE
switch.
®I
REV. FEB 1974
4-11